The invention concerns a cage for a rolling bearing, said cage comprising a first side ring and a second side ring that are connected to each other by crossbars so that pockets for receiving rolling elements are formed, and lubrication grooves extend in axial direction up to said first and second side rings on at least one of peripheral surfaces and bore sections of the crossbars.
A cage of the pre-cited type is known from the German utility model application G 93 06 319.9. The crossbars connecting the side rings of this cage comprise on their outer and/or inner peripheral surfaces continuous, axially extending lubrication grooves. A drawback of this arrangement is that lubricant flow through a bearing having such a cage is relatively weak due to the small distance between the outer peripheral surface of the cage and the outer raceway. If this lubrication groove were to be deepened in radial direction, the problem would arise during the automatic filling of the cage with rollers that under certain circumstances, the sensor might identify the lubrication groove as a continuous rolling element pocket and an attempt would be made to insert a rolling element into this lubrication groove. It is quite obvious that this can lead to a destruction of the bearing cage.
It is therefore an object of the invention to provide an improved rolling bearing cage of the pre-cited type which permits a larger flow of lubricant through the bearing.
It is another object of the invention to provide an improved rolling bearing cage of the pre-cited type that causes no problems during the automatic filling of the pockets with rolling elements.
These and other objects and advantages of the invention will become obvious from the following detailed description.
The invention achieves the above objects by the fact that flow channels are arranged in a fractional region of the lubrication grooves and are set back relative to the lubrication grooves in at least one of a radially inward and a radially outward direction.
By this measure of the invention, additional space is created for the lubricant so that, for example, lubrication of the bearing is possible for its entire life. Besides this, lubricant flow through the bearing is increased so that a better cooling of the bearing by a heightened removal of undesired heat and an improved flushing of dirt particles from the bearing can be realized. In addition, due to the enlarged space for the lubricant, the flow resistance of the bearing as a whole is reduced. A further advantage is that, in spite of the fact that the flow channels deepen the lubrication grooves, these are not identified as pockets during the automatic filling of rolling elements into the cage so that no rolling elements are forced into the lubrication grooves. This is achieved by the fact that the set back flow channels extend only over a part of the extent of the lubrication grooves.
The flow channels of the invention can be configured in many different ways. The decisive feature in each case is that the flow channels should extend only over a fractional region of the lubrication grooves. In one embodiment, the flow channels are configured in the region of the first side ring as two sub channels that are spaced from each other in peripheral direction and merge into each other in a central portion to split up into two sub channels spaced apart in peripheral direction in the region of the second side ring.
In another embodiment, this configuration is reversed i.e., in the region of the first side ring, the flow channels are configured as a single sub channel that splits up in the central portion into two sub channels spaced apart in peripheral direction which, in the region of the second side ring again merge into each other to form a single sub channel.
In still another embodiment, the flow channels are configured in the region of the first side ring as two sub channels that are spaced from each other in peripheral direction, then merge into each other at one point and, continuing from this point, they separate again from each other, so that in the central portion, two peripherally spaced apart sub channels are formed that merge again into each other at a second point and then separate again from each other, so that, in the region of the second ring, two sub channels spaced from each other in peripheral direction are formed.
According to another additional feature of the invention, at least one empty pocket is arranged in the central region of the flow channels. By this measure, the permeability of the cage to lubricant is further enhanced. A further advantage of the invention is obtained by another feature according to which the flow channels comprise, on either side of the central region, a connection to the pockets for receiving the rolling elements.
According to another provision of the invention, the axial dimension of the empty pocket is different from that of the pockets which receive the rolling elements, and the empty pocket may be filled with an additional rolling element.
The invention further provides that the side rings of the cage comprise a bevel. The inclined surface of this bevel facilitates the mounting of the cage, for example, into an associated housing.
Finally, according to a last provision of the invention, a further improvement of lubricant flow through the bearing cage is effected by arranging a further flow channel in the side rings in the region of the rolling elements.
The invention will now be described more closely with reference to the appended drawings.